Except the vertebral injury caused from fracture, most traditional vertebral diseases are relating to the atrophy caused by pathological changes located between intervertebral disks, such that the intervertebal intervals become smaller which also cause intervertebral foramens (nerve foramens) between intervertebral joints narrowed, and thus, the spinal nerve root will be stressed to cause paralysis or pain.
Currently, the therapy manner for the above problem is to implement pedicle screw to pull apart the intervertebral interval, or to implement artificial intervertebral cage or spacer for filling the interval so as to increase thereof and also enlarge the nerve foramen. There already have many similar inventions for fixing the vertebra and normalizing the intervertebral interval through pulling. For example, R.O.C Patent Application No. 093205661 “spinal fixer structure” discloses a fixer utilizing a first shaft and a second shaft as a set to connect plural pedicle screws so as to be mutually connected and have a moving space. However, in this manner, the pedicle screw has to be implemented into the spine for fixation which obviously will destroy the spine so that it actually is dangerous and complicated. Another method is to implement the artificial intervertebral cage or spacer into the interval, as disclosed in R.O.C Patent Application No. 091215377 “A scarf supporting reposition device used for cervical vertebra”, in which the device will be filled between the vertebras so as to distract thereof. However, identically, it also has some limitation and difficulty. There are many disclosures, such as R.O.C Patent Application No. 091216805, No. 091213154, No. 091212198, and No. 091208091, devoted to reduce the danger and complicity as correcting the vertebra, but it still lacks of a convenient, safe and structure simple vertebra correction device. The key for solving the above problem is how to expand the nerve foramen and release the stressed nerve root and simultaneously make the surgery simple and effective, so that if the interspinous process between the two adjacent vertebras can be directly distracted by a specific device, then the stress on the nerve root can be released so as to cure the paralysis or pain.